I am wondering are you using some external framework angular/react or just "only" js?

"Or even deeper, does an over-reliance on documentation indicate a lack of critical expertise that will ultimately result in considerably lower job performance?"

I don't think so, and I don't know why relying on documentation would be bad.

In a more general sense even for making a todo list app I'd imagine the fundamentals aren't changed even across frameworks e.g. of when adding a todo it needs to be added to some sort of a list.

So in my metaphor, that would be like perhaps a gardener assembling irrigation, or someone in a mechanical trade fixing the gasket. There's still a ton of specific knowledge to the job in question.

Of course, it shouldn't be that Google specifically is necessary - just some literature or reference source (i.e. consulting with someone).